title: Prevalence of hepatitis delta virus (HDV) infection in chronic hepatitis B patients with unusual clinical pictures.
abstract: BACKGROUND
  Probably 5% of the HBV carriers have HDV super infection. The risk of fulminant hepatitis, cirrhosis and hepatocellular carcinoma is higher in superinfection than the settings when HBV is alone.
  
  
  OBJECTIVE
  The aim of this study was to evaluate the prevalence of HDV in Iranian HBV isolates and to compare their clinical and virological pictures as well as their HDV genetic variations with other worldwide isolates.
  
  
  METHODS
  81 carriers with positive results for HBsAg with upper limit ranges of ALT and low or undetectable levels of HBV viral load who did not respond to HBV therapy were selected. After RT amplification of HDV Delta antigen, direct sequencing and phylogenetic study were performed to explore the genotype(s) and nucleotide/amino acid variations.
  
  
  RESULTS
  12 (14.8%) patients had positive results for both HDV RNA and anti-HDV. The mean ALT level was higher in HDV positive patients (75.9 U/ML) than HBV-mono-infected individuals; however, the mean HBV viral load was lower in coinfected patients than HBV-mono-infected patients. Phylogenetically, genotype I was the only detected genotype, and the most closely related isolates were of Turkish, Italian and Mongolian origin. Within the delta Ag, there were 326 nucleotide mutations, of which 111 and 215 were silent and missense, respectively. The total number of amino acid substitution was 148; most were located in known functional/epitopic domains. There was no correlation between the numbers of amino acid mutations, with clinical, virological status of the patients.
  
  
  CONCLUSIONS
  HDV should be suspected in HBV carriers with unusual clinical and virological pictures. Relatedness of Iranian HDV isolates to Italian and Turkish sequences proposed a common Caucasian origin for the distribution of HDV genotype I in this ethnic group.
authors.affiliation: Hepatitis B Molecular Laboratory, Department of Virology, School of Public Health, Tehran University of Medical Sciences, Tehran, IR Iran.
authors.forename: Shiva
authors.initials: S
authors.lastname: Ghamari
authors.forename: Seyed Moayed
authors.initials: SM
authors.lastname: Alavian
authors.forename: Mario
authors.initials: M
authors.lastname: Rizzetto
authors.forename: Antonella
authors.initials: A
authors.lastname: Olivero
authors.forename: Antonina
authors.initials: A
authors.lastname: Smedile
authors.forename: Abulfazl
authors.initials: A
authors.lastname: Khedive
authors.forename: Seyed Ehsan
authors.initials: SE
authors.lastname: Alavian
authors.forename: Mohammad Reza
authors.initials: MR
authors.lastname: Zolfaghari
authors.forename: Seyed Mohammad
authors.initials: SM
authors.lastname: Jazayeri
keywords: Antibodies; Hepatitis Delta Virus; Prevalence